TY - JOUR

T1 - Comparison of stellar populations in simulated and real post-starburst galaxies in MaNGA

AU - Zheng, Yirui

AU - Wild, Vivienne

AU - Lahen, Natalia

AU - Johansson, Peter H.

AU - Law, David

AU - Weaver, John R.

AU - Jimenez, Noelia

PY - 2020/8/17

Y1 - 2020/8/17

N2 - Recent integral field spectroscopic (IFS) surveys have revealed radial gradients in the optical spectral indices of post-starburst (PSB) galaxies, which can be used to constrain their formation histories. We study the spectral indices of post-processed mock IFS datacubes of binary merger simulations, carefully matched to the properties of the MaNGA IFS survey, with a variety of black hole (BH) feedback models, progenitor galaxies, orbits, and mass ratios. Based on our simulation sample, we find that only major mergers on prograde-prograde or retrograde-prograde orbits in combination with a mechanical BH feedback model can form galaxies with weak enough ongoing star formation, and therefore absent H alpha emission, to be selected by traditional PSB selection methods. We find strong fluctuations in nebular emission line strengths, even within the PSB phase, suggesting that H alpha selected PSBs are only a subsample of the underlying population. The global PSB population can be more robustly identified using stellar continuum-based approaches. The difficulty in reproducing the very young PSBs in simulations potentially indicates that new sub-resolution star formation recipes are required to properly model the process of star formation quenching. In our simulations, we find that the starburst peaks at the same time at all radii, but is stronger and more prolonged in the inner regions. This results in a strong time evolution in the radial gradients of the spectral indices that can be used to estimate the age of the starburst without reliance on detailed star formation histories from spectral synthesis models.

AB - Recent integral field spectroscopic (IFS) surveys have revealed radial gradients in the optical spectral indices of post-starburst (PSB) galaxies, which can be used to constrain their formation histories. We study the spectral indices of post-processed mock IFS datacubes of binary merger simulations, carefully matched to the properties of the MaNGA IFS survey, with a variety of black hole (BH) feedback models, progenitor galaxies, orbits, and mass ratios. Based on our simulation sample, we find that only major mergers on prograde-prograde or retrograde-prograde orbits in combination with a mechanical BH feedback model can form galaxies with weak enough ongoing star formation, and therefore absent H alpha emission, to be selected by traditional PSB selection methods. We find strong fluctuations in nebular emission line strengths, even within the PSB phase, suggesting that H alpha selected PSBs are only a subsample of the underlying population. The global PSB population can be more robustly identified using stellar continuum-based approaches. The difficulty in reproducing the very young PSBs in simulations potentially indicates that new sub-resolution star formation recipes are required to properly model the process of star formation quenching. In our simulations, we find that the starburst peaks at the same time at all radii, but is stronger and more prolonged in the inner regions. This results in a strong time evolution in the radial gradients of the spectral indices that can be used to estimate the age of the starburst without reliance on detailed star formation histories from spectral synthesis models.

KW - galaxies: evolution

KW - galaxies: interactions

KW - galaxies: star formation

KW - galaxies: stellar content

KW - STAR-FORMATION HISTORIES

KW - DELTA-STRONG GALAXIES

KW - SMOOTHED PARTICLE HYDRODYNAMICS

KW - QUASAR OUTFLOW CONTRIBUTION

KW - ACTIVE GALACTIC NUCLEI

KW - DIGITAL SKY SURVEY

KW - EVOLUTIONARY SEQUENCES

KW - BLACK-HOLES

KW - RADIATIVE OPACITIES

KW - E+A-GALAXIES

U2 - 10.1093/mnras/staa2358

DO - 10.1093/mnras/staa2358

M3 - Journal article

VL - 498

SP - 1259

EP - 1277

JO - Royal Astronomical Society. Monthly Notices

JF - Royal Astronomical Society. Monthly Notices

SN - 0035-8711

IS - 1

ER -